The present invention relates to an improved structure of a transformer having improved core assembly structure.
The core of the present transformer has two magnetic paths with windings (a main winding and a control winding), and can be utilized as a firing transformer for a gas discharge lamp or a variable inductance element. The Japanese patent laid open publication 10221/80, which has the convention priority based upon the U.S. patent application Ser. No. 969381, shows the use of that kind of transformer for a gas discharge lamp. Further, the present transformer can be used as a variable inductance element which is utilized for a tank circuit (resonator) in a wireless radio set or a television set for tuning purposes. When the transformer is utilized for a firing transformer of a gas discharge lamp, the two magnetic paths may either be dependent upon each other, or independent from each other. When two magnetic paths are independent from each other, the present transformer is substantially the same as two separate transformers having a control winding on a closed first core, and a main winding on the other core.
A prior core for this kind of transformer is shown in FIGS. 1 and 2, in which the reference numeral 1 shows the laminated silicon steel plates which are E shaped, and 3 is a small window provided on one side of the plates. A pair of E-shaped plates align to produce a substantially 8-shaped plate as shown in FIG. 1, and the lamination of the 8-shaped plates provides the main magnetic path for the transformer. The main winding 4 is wound on the center leg of said 8-shaped core, and the control winding 2 is wound through the window 3.
In the above structure, the main windings 4 can be wound using a winding machine on a bobbin (not shown). After the main winding 4 is wound on a bobbin, a pair of E-shaped cores are inserted in the bobbin to provide a closed magnetic path. But, a control winding 2 must be wound manually through the window 3. Due to the manual winding operation, it takes a long time to produce a transformer, and very often, a coil to be wound is subject to damage in the manual winding process.